assert that vtk file opening succeeds
re-implemented ShrinkPartition, not MDS-specific

currently the albany/ subdir implements partition
shrinking but depends on mds-specific calls.
it should be possible to replicate those using
only apf calls, so we're trying that.
parma.h needs Mesh2.h again, for ShrinkPartition
actually add the shrink code to the build
first round of fixes to shrink code
second round of fixes

tested by a modified ma_test,
this adapted a 4-part mesh on 2 procs